AIDS is associated with marked catabolism and increased rates of whole body protein turnover, as is cystic fibrosis. The PI has demonstrated decreased insulin sensitivity in CF patients, which is exacerbated during acute illnes and is associated with weight loss. The aim of this pilot study is to evaluate carbohydrate and protein metabolism in AIDS patients. The hypothesis is that insulin resistance occurs in AIDS patients and is exacerbated by acute illness, and that it contributes to the nutritional wasting seen in these patients.